| Thread Links | Date Links | ||||
|---|---|---|---|---|---|
| Thread Prev | Thread Next | Thread Index | Date Prev | Date Next | Date Index |
|
That's definitely one way it can be interpreted.
There is some apples and oranges comparison going on there, and I'm not sure how
the VG got added to the 802.3 mix. ;-)
But with optics, I would agree that the tougher choices
haven't always been made, even when the writing was on the wall. The
biggest complaint with 10GbE was all the possible port types (thank you WAN
interface sublayer). The 10GBASE-SR PHY is doing well in the market
though, and that's partially due to the fact that it is the only 850nm
wavelength PHY for that space. Interestingly
enough though, implementations can be achieved with either linear or limiting
components. And, if you put a linear at one end and a limiting at the
other, they will communicate.
That's what I do like about Ali's proposal. He
has shown that it is possible to do 300m of MMF with an linear approach.
That indicates to the task force there is more margin in a linear approach than
in a limiting approach; therefore, having more margin to play with, the linear
approach with a 100m MMF reach should be able to become the lowest cost solution
for the largest volume of the MMF market. That's a huge benefit.
Rather than trying to pushing the limits and slowing the adoption curve, there
is an implementation option which should make 100G MMF up to 100m a fiscally
viable option.
Thanks,
Brad From: Kevin Brown [mailto:kbrown@BROADCOM.COM] Sent: Tuesday, March 25, 2008 12:25 AM To: STDS-802-3-HSSG@LISTSERV.IEEE.ORG Subject: Re: [802.3BA] Longer OM3 Reach Objective "Let the market decide" was how we ended up with
100BASE-TX, instead of 100BASE-T4, 100BASE-T2, or 100BASE-VG. The 802.3
working group did a poor job of making tough decisions and minimizing the number
of options to be presented to the industry.
What a mess.
But I think 100BASE-TX is the most widely
deployed of the various 802.3 interfaces. There have
been a few billion shipped so far.
KB
From: Brad Booth [mailto:bbooth@AMCC.COM] Sent: Monday, March 24, 2008 3:19 PM To: STDS-802-3-HSSG@LISTSERV.IEEE.ORG Subject: Re: [802.3BA] Longer OM3 Reach Objective "Let the market decide" is a really, really bad way to
write a standard. The IEEE 802.3 working group has done a very good
job of making tough decisions and minimizing the number of options to be
presented to the industry. To create a reach objective that can only be
satisfied by one implementation is a poor choice as
it reduces the ability of component vendors to compete based upon
their respective implementation strategies. As the current objective is
written, the reach is achievable with limiting and linear TIA's and may be
achievable with lower cost components.
Just my 2 cents,
Brad
From: Ali Ghiasi [mailto:aghiasi@BROADCOM.COM] Sent: Monday, March 24, 2008 4:58 PM To: STDS-802-3-HSSG@LISTSERV.IEEE.ORG Subject: Re: [802.3BA] Longer OM3 Reach Objective Thanks for sending the pointer to the top 500 list and I do see the server at TJW. In November 2007, 2 systems appeared in the TOP500 list.
They did not show a picture or how big is the server, but based on your remarks it is small enough to fit in modest room. I assume the Intra-links with the Blue Gene might be proprietary or IB. What does clustering system Intra-links has do to with the Ethernet network connection. I assume still some of the users in TJW lab may want to connect with higher speed Ethernet to this server, very likely you will need links longer than 100 m. In addition higher speed Ethernet may be used to cluster several Blue Gene system for fail over, redundancy, disaster tolerance, or higher performance which will require links longer than 100 m. We are both in agreements that parallel ribbon fiber will provide the highest density in near future. The module form factors with a gearbox will be 3-4x larger. Here is a rough estimate of BW/mm (Linear face plate) for several form factors: Speed Media Sig. Form Factor Bandwidth (Gb/mm) 10GbE 1x10G SFP+ (SR/LR/LRM/Cu ) 1.52 (Assumes stacked cages) 40 GbE 4x10G QSFP (SR or direct attach) 4.37 (Assumes stacked cages) 40 GbE TBD If assumed Xenpak (LR) 0.98 100 GbE 10x10G CSFP (SR or direct attach) 3.85 (The proposed connector already is stacked ) 100 GbE 4x25G CFP (LR) 1.23 As you could see here the form factors which allow you to go >100 m will be several time larger and not compatible with the higher density solution based on nx10G. Linear nx10G as given in http://www.ieee802.org/3/ba/public/jan08/ghiasi_02_0108.pdf can extend the reach to 300 m on OM3 fiber and relax the transmitter and jitter budget. You have stated strongly you see no need for more than 100 m, but we have also heard from other who stated there is a need for MMF for more than 100 m especially if you have to change the form factor for more than 100m! Like FC and SFP+ we can define limiting option for 100 m and linear option for 300 m, and let the market decide. Thanks, Ali Petar Pepeljugoski wrote: OF4D7F1939.EE7C74E4-ON8525740D.000B4235-8525740D.000CD5A7@us.ibm.com type="cite"> |